1. Field of the Invention
This invention relates to golf clubs. Specifically, the present invention relates to a set of irons dimensioned and configured to permit the user to maintain the same swing for each.
2. Description of the Prior Art
For clarity, the three-dimensional Cartesian coordinates referred to herein are oriented such that the reference plane is generally horizontal and defines the X-Y plane. In most cases, the reference plane contains the players two feet and the ball. The players feet lie along the X-axis. The Y-axis intersects the X-axis between the players feet and extends forward through the ball. The Z-axis extends orthogonally up from the intersection of the X-and Y-axes.
Golf is an exceedingly difficult sport. Golfers must master a plurality of static and dynamic variables in order to play the game with any modicum of success. Golf club characteristics play a significant role in the type and severity of variables encountered.
Golf clubs have four basic attributes which often vary from club to club: (1) weight; (2) length from the top of the handle to the heel of the club; (3) loft angle of the face that contacts the ball relative to the reference plane; and (4) lie angle of the shaft relative to the reference plane. Diversity in club attributes, unfortunately, means that a golfer's mastery of the variables to properly play one club will not necessarily lend to well-tempered play of another.
Reduction of club attribute variability reduces the overall number of variables with which golfers must contend. Ideally, constructing a set of clubs that permits a golfer to use the same stroke for each club grants golfers the luxury of concentrating more effort toward learning and perfecting that one stroke. Matched golf sets which purport to be designed for a universal club stroke enhance the sport and provide greater enjoyment to players.
Several types of matched golf club sets are described in the literature. For example, U.S. Pat. No. 3,751,035, issued Aug. 7, 1973, to John W. Lockwood, describes a set of golf club irons. The clubs have elliptical faces of common area. The sweet spot of each face, the most effective part of the club for striking a ball, is centered within the face of the club.
U.S. Pat. No. 3,984,103, issued Oct. 5, 1976, to Jack W. Nix, describes a set of golf clubs including woods and irons. The clubs falling into the "wood" class have the same length, lie angle, swing weight and total weight. Similarly, the clubs falling into the "iron" class have the same length, lie angle, swing weight and total weight. The invention also provides for the clubs falling into both the "wood" and "iron" classes all having the same length, lie angle, swing weight and total weight.
U.S. Pat. No. 4,147,349, issued Apr. 3, 1979, to Phillippe M. Jeghers, describes a set of golf club irons. Each club head defines the same frontal area. The frontal area is shown as being the projection of the face in the Y-Z plane. Club face surface area increases as loft angle decreases to maintain the same projection as the other clubs. Each club, when in contact with the ball, has its center of gravity located at the same distance from the reference plane as the others. Positioning of the center of gravity relative to the club face differs according to loft angle.
U.S. Pat. No. 4,679,791, issued Jul. 14, 1987, to Donald R. Hull, describes a set of golf club woods and irons. The clubs falling into the "wood" class have the same weight, length, and lie angle. Similarly, the clubs falling into the "iron" class have the same weight, length, lie angle. The clubs falling into both the "wood" and "iron" classes have heads in which the center of gravity is facially centered. The invention also describes each club having a grip with a flattened elliptical shape, the elongated portion of the grip being disposed along the Y-axis.
U.S. Pat. No. 4,941,666, issued Jul. 17, 1990, to Noriyuki Suganuma, describes a set of golf club woods and irons. The clubs are configured such that head mass increases as shaft length decreases. Club length is described as being inversely proportional to the second moment of inertia about an axis defined by the grip and club mass center. The length also may be related to the natural frequency of the club. The weight of the club is described as varying according to the particular function for which the club is used, such as putting or chipping.
U.S. Pat. No. 4,971,321, issued Nov. 20, 1990, to C. Michael Davis, describes a set of golf club woods and irons. The clubs falling into the "wood" class have the same length, shape, and mass differing only in loft angle. The clubs falling into the "iron" class are further segregated into three subclasses. The clubs falling into each subclass have the same length, shape, and mass differing only in loft angle. The clubs falling into both the "wood" and "iron" classes each maintain the same distance between a lower grip line, a line falling below the bottom hand, and the hosel or heel of the club. The clubs having longer overall shaft lengths have more grip extended above the top hand for maintaining greater counterbalancing than the shorter clubs.
U.S. Pat. No. 5,029,864, issued Jul. 9, 1991, to Michael B. Keener, describes a set of golf club irons. The clubs have common weight and length. Each club has a face including multiple horizontal, V-shaped scoring. The V-shaped groove is purposed at imparting backspin on a golf ball. The V-shape has a normal and a contact face relative to the face of the club. The normal face is the upper shelf of the V-shape. The angle of the normal face relative to the face of the club depends on the loft angle of the club and is configured to be substantially not in contact with the ball. The normal face extends into the face of the club no more than 5 mm. The contact face extends from the deepest point of the normal face downward and outward. The angle between the contact face and the club face ranges between 30.degree. and 70.degree..
U.S. Pat. No. 5,228,688, issued Jul. 20, 1993, to C. Michael Davis, a continuation-in-part to U.S. Patent No. 4,971,321, describes a set of golf club woods and irons. The clubs have common upper and lower grip lines. However, each club has a different length, weight and lie angle with respect to the others.
European Patent No. 0517487A1, published Dec. 9, 1992, issued to Acushnet Co., describes a set of golf club irons. The back cavity of each club is configured such that the center of mass and club head coincide.
None of the above references, taken alone or in combination, are seen as teaching or suggesting the presently claimed matched golf club set.